Archive for the ‘Agricultural and Inspection’ Category

Deep learning algorithms have taught these aerial robots how to follow an unfamiliar path.

Autonomous drones have already mastered the wide-open skies. DHL, Amazon, and Google have each demonstrated self-piloting drones that can deliver packages — in fact, the latter two, as The Vergerecently reported, are ready to implement full-scale drone delivery operations in the US and are simply waiting on regulators to get out of the way. But drones that can fly autonomously in complex environments with multiple obstacles (i.e. not the wide-open sky) are another story.

Navigation in terrains that are densely populated with obstacles is an ongoing challenge for researchers. There’s been some headway by a team at MIT, who last November demonstrated an autonomous drone avoiding trees while flying at high speeds in a wide-open field. Now, a group of Swiss researchers have developed technology that allows drones to autonomously navigate forest trails, a development they say could one day aid in search-and-rescue operations.

The group, comprised of researchers from the Dalle Molle Institute for Artificial Intelligence, the University of Zurich, and NCCR Robotics, used deep learning neural networks to tackle the challenge of training an autonomous drone to navigate a densely wooded forest. Teaching a computer to recognize the direction of a trail is a complex task. It can even be difficult for a human to determine the direction of a trail. Just take a look at these photos of trails taken by the researchers and try to determine which direction they’re headed in:

In order to train their algorithm, the researchers mounted three GoPro cameras to a headset and took off on hiking trails across the Swiss Alps. One camera was pointed ahead of the hiker, one to the left, and one to the right. After hours spent on these trails, the researchers had snapped over 20,000 images (images in front of the hiker and on either side). Then they used these images to teach their algorithm what the boundaries of a hiking trail should look like.

The result was a deep-learning algorithm that allows a drone equipped with a single forward-facing color camera to navigate a previously-unseen trail completely on its own — no human interaction whatsoever. The algorithm, the researchers claim, was even better than humans at determining the correct direction of the trails it traveled on, guessing the correct direction of a trail with 85 percent accuracy. Humans tasked with determining the direction of the same trails were able to do so correctly only 82 percent of the time.

The team cautions that these results are still in very preliminary stages. But while there’s a lot more work to be done before autonomous drones will be able to search forests for missing people, the researchers believe their work is a good sign of how deep neural network will allow autonomous vehicles to navigate situations that involve complex and highly dimensional inputs.

Unmanned inspection vehicles will increase safety and efficiency for the freight network.

After years of accusations of foot-dragging on unmanned aerial vehicle (UAV) regulation, the Federal Aviation Administration has recently been speeding exemption approvals and announcing new regulatory programs. One beneficiary is BNSF Railway, which has gained approval for a pilot(less) programto use drones to inspect its far-flung network of rails. The inspections could help reduce derailments and other safety problems—and though BNSF isn’t saying so, lead to lower labor costs in the long run.

Rail safety is drawing new focus after May’s catastrophic Amtrak derailment. Though that accident’s immediate cause was excessive speed, the Federal Railroad Administration reports that nearly 500 derailments were caused by defective track in 2014, making up more than a third of total rail accidents. Those derailments caused 35 injuries and $94 million in damages last year. BNSF says its drones will allow for more frequent track inspections, which should reduce track-caused derailments.

FILE – In this Nov. 6, 2013, file photo, a BNSF Railway train hauls crude oil near Wolf Point, Mont. A collapse in oil prices won’t derail the railroads profit engine even if it does slow the tremendous growth in crude oil shipments seen in recent years. Railroads went from hauling 9,500 carloads of crude oil in 2008 to 435,560 last year, as production boomed and oil routinely sold for $90 a barrel or more. But even with the surge, crude oil shipments remain less than 2 percent of all the carloads major U.S. railroads deliver. (AP Photo/Matthew Brown, File)

The FAA has greenlit more than 400so-called “333 exemptions” for limited drone operations since this February. But unlike most operators, BNSF will be testing UAV’s outside of direct visual contact with their operator, referred to as “beyond visual line of sight,” or BVLOS, operation.BVLOS operation is regarded as more risky by the FAA.

BNSF has earned this special right as part of the FAA’s Pathfinder program, an initiative to develop UAV regulation in collaboration with industry that was announced in May. CNN and the drone systems maker PrecisionHawk USA are the other two inaugural participants, and the FAA has invited applicants from other sectors.

The ability to fly drones long distances is crucial to BNSF’s goals for the program. The railway owns over 32,500 miles of rail line across the U.S., and says that every foot of track is inspected in person twice a week. But some of that track is hundreds of miles from any major population center, increasing the expense and inconvenience of manned inspection. BNSF has emphasized that its drone program would allow for more frequent inspections, rather than replacing human crews.

Herding cattle. Counting fish. Taking an animal’s temperature. Applying pesticides. When it comes to drones, “your imagination can go pretty wild in terms of what would be possible,” says Roger Johnson, president of the National Farmers Union. This month, the Federal Aviation Administration issued the first permit for agricultural use of unmanned aerial vehicles. Steven Edgar, president and CEO of ADAVSO, says his Idaho-based business will use a lightweight, fixed-wing drone to survey fields of crops.

Drone technology, already used in other countries, can make farmers more efficient by helping them locate problem spots in vast fields or ranchlands. Increased efficiency could mean lower costs for consumers and less impact on the environment if farmers used fewer chemicals because drones showed them exactly where to spray.

The Association for Unmanned Vehicle Systems International, a trade group, says agriculture could account for 80 percent of all commercial drone use, once government regulations allow it. That could be a while. The Federal Aviation Administration has been working for years on rules that would balance the desire for commercial flights of small drones with the need to prevent collisions involving manned aircraft.

Five ways drones could affect the food supply:

SCOUTING FARMS

The first agriculture drones are looking at massive fields of crops to scout out where crops are too wet, too dry, too diseased or too infested with pests. They can help farmers count plants or measure their height. Farmers can now use satellite technology, but it’s slower and less detailed than images from low-flying drone.

“This is about getting the most productivity from every square inch of a farm,” says ADAVSO’s Edgar.

Alabama farmer Don Glenn said he would buy a drone or use a service that provides drone surveillance on his farm of corn, wheat, soybeans and canola. It’s hard to survey corn fields when they are 8 feet to 10 feet tall, he says.

Drones can carry different tools, including high-resolution cameras, infrared sensors and thermal sensors. Ground-penetrating radar could even measure soil conditions.

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APPLYING CHEMICALS

Once the land is surveyed, farmers could use that data to narrow the areas that need treatment. If a plot of farmland is infested with weeds, for example, a farmer could spray a small amount of herbicide just in that area, instead of an entire field, to kill them. Farmers hope that they eventually could use drones to do the spraying.

Kevin Price of the Iowa-based drone company RoboFlight Systems says that kind of precision would put farmers at a huge advantage, helping them reduce the costs of chemicals and their application.

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PLAYING COWBOY

The National Farmers Union’s Johnson says his father used to fly a plane over his ranch and his neighbors’ to spot escaped cattle when he was growing up in North Dakota. That’s something a drone could do with far less money and effort.

Lia Reich of the UAV manufacturer PrecisionHawk says the company’s drones can use thermal sensors to take the temperature of cattle. The data comes back as bands of color, and “if all of the cattle look green and one looks dark purple then that one has a higher temperature,” she said.

The South Lawn of the White House in Washington is seen on Monday, Jan. 26, 2015. A device, possibly …

Drones could help ranchers count cattle, disturb pests that are aggravating livestock or even apply insecticide to an animal.

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FINDING FISH

A University of Maryland project is developing drone technology to monitor fish in the Chesapeake Bay. Matt Scassero, the project director, says the idea is that a laser-based sensor mounted on a drone would allow scientists to see through the water and measure the size of a school of fish. Researchers could ascertain the conditions of the water, too.

Some drones can land on water, making it possible to measure water quality, as well.

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REVEALING SECRETS

There are downsides for farmers. Documentary filmmaker Mark Devries has used an unmanned vehicle to fly over large commercial hog operations and film them. He wants consumers to see the buildings full of animals and huge manure pits.

R.J. Karney of the American Farm Bureau Federation says there is a “major concern” about those kinds of films and his group intends to work with the Obama administration and Congress to address it. He says such films are not only a privacy violation, but can put farmers at a competitive disadvantage.

Still, the agriculture industry sees the advantages of drones as far outweighing the disadvantages.

“We’re concerned about falling behind other countries” as the FAA delays, Karney says. “Farmers are anxious to see where this can go.”

U.C. Davis engineer Ryan Billing flies a Yamaha RMAX helicopter over the Oakville Station test vineyard to demonstrate the use of the drone applying fertilizers and pesticides to vineyards. (JOHN BURGESS/ PD)

As he went around Napa Valley in the past two years, Ken Giles had the unenviable task of notifying nearby residents that UC Davis would be conducting a demonstration project using drones to spray pesticides at its vineyard in Oakville.

Giles, a professor in the university’s biological and agricultural engineering department, said he was prepared for questions, especially given the civil rights qualms over military and police use of drones.

“I would go out and say, ‘I’m here to talk on drones spraying pesticides.’ If I was spraying over GMO crops, then I would have been three for three (on paranoia),” Giles wryly noted, referencing concerns over genetically modified organisms.

But Giles said he has not experienced much uproar over the program with partner Yamaha Motor Corp. USA, which has used its RMAX helicopter to test the efficiency and safety of aerial spraying over the Oakville vineyard. “It seems to be quieted down a bit,” he said.

The drones are expected to be more commonplace in the Napa vineyard, likely by next year if the Federal Aviation Administration approves Yamaha’s application to use unmanned aircraft systems for agricultural purposes.

Such approval appears increasingly likely as the FAA on Sept. 25 authorized six aerial photo and video production companies to use drones in the film and television industry.

“We feel the timing is right to investigate the U.S. market. We have been doing it the last couple years,” said Steve Markofski, business planner for Yamaha. “We have been focusing on high-value crops, specifically grapes here in Napa.”

Yamaha and UC Davis conducted a demonstration of the RMAX helicopter on Wednesday in conjunction with the Association for Unmanned Vehicle Systems International, a trade group which supports the defense, civil and commercial sectors. The aircraft, a small helicopter that weighs 140 pounds, carried water in its 2.1-gallon tanks, instead of pesticide.

Officials at the event were on message to continually utter the phrase “unmanned aircraft” as opposed to drones, which carry a more sinister meaning.

So far, the opposition to commercial use of drones is not as intense as that for military and police use.

“Our primary and basically exclusive focus has been and will continue to be on the use of drones by law enforcement,” said Will Matthews, senior communications officer for the ACLU of Northern California, via email.

Japan pioneered the use of drones in agriculture during the early 1990s, and now unmanned aircraft farm up to 40 percent of that country’s rice crop. Australia also uses drones for agricultural purposes.

Yamaha’s pitch for the American market is simple: the unmanned aircraft can save money, time and be more efficient than the traditional method of spraying by either tractor or by hand.

For example, the RMAX, flying approximately three meters above the vines at a speed up to 20 kilometers per hour, can cover up to 12 acres an hour. In contrast, a tractor can cover one acre. “We’re quite a bit faster compared to the current method,” Markofski said.

If approved, Yahama would likely target hilly vineyards, such as those along the Mayacmas Mountains, where spraying is much more difficult and time consuming. It also would apply for use in Yamhill County, Ore., which also has many wineries.

“Can you imagine treating those (hilly vineyards) with a ground tractor, how narrow those (fields) are and how risky that can be?” Markofski said.

The drones also can apply fertilizer and seeds as well as monitor crops. Yamaha would lease the aircraft, operated by a three-man team. The operator must remain up to 150 meters near the drone.

Yamaha is still formulating the price of the drones, pending approval, Markofski said.

UC Davis continues to crunch data from the test flights to monitor the drones’ efficiency, productivity and spray drift, Giles said. But so far there have been no red flags, especially in its safety.

“It’s a vehicle with potential where we know there are things we can do with it that we couldn’t do in the past — spot treatments, quick treatments, delivery of a very localized payload,” Giles said.

A drone lifts off at Kunde Family Vineyards near Santa Rosa, Calif. Ryan Kunde, a winemaker at DRNK Wines, flies his drones recreationally and has been testing drones with the goal of one day using them to help make decisions in the vineyard.

When Steve Morris began building unmanned aerial systems in the late 1990s, he envisioned flying them over fields and collecting data that would be useful to farmers.

But after the wars in Afghanistan and Iraq, drones became largely associated with military strikes and surveillance operations. Morris said the technology became the subject of contentious political debates and public paranoia.

“The entire dream evaporated at that point,” said Morris, founder and president of MLB Co. in Santa Clara, Calif. “In an alternate universe where [drones] rose to prominence through helping the economy, creating businesses and jobs, people would have a different view of them.”

More than a decade later, attention is refocusing on development of drones for commercial purposes. Amazon.com Inc., Google Inc. and Walt Disney Co. are grabbing headlines with plans to develop drones for deliveries, mapping and entertainment. I think it’s going to change agriculture as we know it in North America. It’s definitely going to allow producers to become much more efficient. – Scott Shearer, a professor at Ohio State University and an expert in precision agriculture

But the big boom in unmanned aircraft may come from what’s known as precision agriculture — using high-tech systems to help farmers increase yields and cut costs.

North Dakota will soon get a glimpse of a future where farmers can monitor their crops using small, flying drones. That’s because the US Department of Transportation’s Federal Aviation Administration (FAA) has given the state the go-ahead to start using its unmanned aerial systems (UAS) test site. It’s the first one to become operation among the six commercial UAS testing program sites chosen by Congress in 2013. The state’s Department of Commerce will hold two rounds of flight tests using Draganflyer X4ES drones not only to monitor crops, but also to test soil quality. These are relatively small, helicopter-like machines, which measure 36.25 inches in length and width and are equipped with Sony cameras.

While the mission’s main goal is to prove that drones can be used for those aforementioned farming tasks, authorities will also be collecting safety data from the flights.

According to FAA Administrator Michael Huerta:

These data will lay the groundwork for reducing risks and ensuring continued safe operations of UAS. We believe the test site programs will be extremely valuable to integrating unmanned aircraft and fostering America’s leadership in advancing this technology.

In other words, missions conducted in the six test sites will determine the future of UAS in the country and perhaps even to make the public realize that not all drones are harbingers of doom. The Draganflyer X4ES drones will take to the skies on the week of May 5th at North Dakota State University’s Carrington Research Extension Center and then again at Sullys Hill National Game Preserve this summer. But, as the permit to operate the site is good for two years, the drone will likely roam more Peace Garden state fields in the future.

A four-rotor, camera-equipped drone hovers during a demonstration flight at a McMinnville, Ore., forum.

Speakers say agriculture will be an early adapter of drone technology.

MCMINNVILLE — Young Kim is a former U.S. Air Force pilot and familiar with the “outcome oriented” use of drone aircraft by the military. Get them over a target, conduct the surveillance or fire the missile – that’s how success is gauged.

Putting drone technology to work in agriculture, as he does now as general manager of Bosh Precision Agriculture in Virginia, requires an entrepreneurial mind-set.

“Do not waste growers’ time,” he said at drone technology forum in the heart of Oregon’s wine country this week. “You’ve got to deliver value very, very quickly. Show them how it will increase yield and lower inputs costs.”

Kim believes unmanned planes, equipped with sensors and cameras, will rapidly transform agriculture by providing quick, detailed information on plant health, soil and water conditions, disease or pest outbreaks and more. He said it’s a change similar to moving from analog to digital technology.

Agriculture is in the midst of a significant transformation, he said. The “biggest ag boom since the 1980s” is accompanied by a trend in which the number of farmers is declining but the acreage farmed by each is increasing, Kim said. At the same time, those farmers working large plots of land want the intimate knowledge they used to have of smaller acreage. Drones can provide that, but Kim said people shouldn’t get hung up on the “sexiness” of the technology.

“The real value is the data,” he said. “Focus on the problem of the grower and work backward from there.”

OKLAHOMA CITY – Privacy concerns weigh heavy on the governmental use of UAS. But for farmers in Oklahoma and all around the United States, UAS could be a necessary tool to the future of farming.

“The technology is pretty new to our members but as we go and technology gets stronger I see a huge market for it in the future,” said Oklahoma Farm Bureau’s John Collison.

UAS is already a tool for many Oklahoma Farmers.

“Check their cattle, check their property, use these drone for precision agriculture and make sure we are farming the most efficient and effective way possible,” Collison said.

Oklahoma Farm Bureau’s John Collison still hears concerns from other farmers across the state.

“Farmers want to use these drones in a correct manner and under FAA guidelines and using them correctly,” Collison said.

In an exclusive statement to News 9, the FAA clarified the issue, stating:

“Farmers may operate an unmanned aircraft over their own property for personal use and Guidelines for the operation of model aircraft, such as those published by the Academy of Model Aeronautics, may be used by farmers as reference for safe model UAS operations.”

One priority guideline from the AMA… “(c) Not fly higher than approximately 400 feet above ground level within three (3) miles of an airport without notifying the airport operator.”

“System are much smaller, and has the capability to sense where his crops need to be watered,” said Retired Major General Toney Stricklin.

Retired Major General of the US Army and member of the Oklahoma Unmanned Aircraft Council Toney Stricklin knows the difference between military and commercial drones, and feels farming is just the beginning.

“I Like to say the genie is out of the bottle. This technology will continue to grow in public safety and agriculture,” Stricklin said.

It really is just the beginning. General Stricklin estimates in the next 20 years, UAS will be a multi-billion dollar industry.

[ For more information about UAV’s positively impacting wildlife, pick up the January/February 2014 issue of Robot Magazine and check out “UAV’s Deployed in Nepal To Save Wildlife”, by Tom Atwood. http://www.botmag.com ]

BARDIA NATIONAL PARK

– Nepal’s antipoaching efforts received a major boost this week as park rangers and army personnel learn how to operate unmanned aerial vehicles (UAVs) in two national parks in a training program organized by WWF.

Nepal is home to rhinos, tigers and elephants, among the world’s most vulnerable species. Poaching of these and many other animals is at an all-time high and the hope is that UAV technology will help capture poachers in the act and deter others from even trying.

WWF has supported Nepal with training rangers to use unmanned aerial vehicles to monitor for poachers.

“Nepal is committed to stopping wildlife crime, which is robbing Nepal of its natural resources, putting the lives of rangers and local communities at risk, and feeding into global criminal networks,” said General Krishna Acharya, Director of Nepal’s Department of National Parks and Wildlife Conservation. “Technologies like these non-lethal UAVs could give our park rangers a vital advantage against dangerously armed poachers.”

Nineteen park rangers and Nepal army personnel were trained to use the UAVs by developer Mr. Lian Pin Koh, an ecologist at the Swiss Federal Institute of Technology Zurich. Participants learned how to use the planes and conducted field tests in Bardia National Park.

Traditionally, effective monitoring of national parks has depended largely on accessibility of the terrain by anti-poaching patrols as well as prior intelligence on poachers in the vicinity.

The UAV gives the patrols a new strategic advantage with an eye in the sky, allowing them access into previously unreachable areas and a safe view of illegal activities on the ground. The presence of a UAV also serves as a deterrent to poachers and illegal loggers since they now know that the parks are being monitored both on the ground and from above.

The GPS-enabled FPV Raptor model planes are light enough to be launched by hand, filming the ground below with a still or video camera. They can fly a pre-programmed route of about 30km at a maximum elevation of 200 meters for up to 50 minutes. The battery can be recharged in about half an hour. Each UAV costs about $2500, making it affordable even for developing countries like Nepal.

“WWF is excited to be part of this field test of new technology in partnership with the government of Nepal,” said Anil Manandhar, Country Representative of WWF Nepal. “We see this as a potentially powerful new tool to improve protection of Nepal’s national parks from illegal activities like poaching and logging.”

Sometimes it’s hard to get the big picture from the ground. In a vineyard, the color of vines and signs of stress are easier to see, especially for a whole field, from the sky. Today, this kind of aerial surveying for agriculture can be done with an appointment and service fee from a manned airplane or helicopter, but in the future it could all be done by drones the farmers’ themselves own.

DRNK Wines, a vineyard located in Sebastolpol, California, recently had 3D Robotics, the drone company founded by former Wired editor-in-chief Chris Anderson, fly a drone over its fields. 3D Robotics specializes in piloting systems for smaller drones, and the vineyard used 3D Robotics’s route-plotting software for mapping out the drone’s precise path. In just an hour, the drone flew over the field snapping pictures, then stiched together the pictures to create a comprehensive map of the vienyard. Looking over the newly created field map, farmer Ryan Kunde noticed two things he expected, and one he didn’t. The top of the hill had darker vines, indictating more water and better soil, than the lower slopes. That variation was expected. Unexpected was a fertile crescent at the bottom of the hill, with darker vines indictating a second especially good growing patch. With that knowledge, Kunde sampled grapes from the crescent, and decided which part of his crop to harvest first.

NOAA has begun testing unmanned aircraft in the Olympic Coast National Marine Sanctuary that could allow researchers to observe animals at relatively close range with minimal disturbance, and possibly locate marine debris in remote areas.

The test of the Puma system, which can fly lower and slower than manned aircraft and are much quieter, is taking place in and around the sanctuary through June 29 and is the first test of unmanned aircraft for use in the Olympic Coast.

During the test, the aircraft is launched and recovered from the research vessel Tatoosh. The test mission will demonstrate the aircraft’s camera resolution and allow researchers to explore the aircraft’s potential to support management of Olympic Coast National Marine Sanctuary, the Washington Maritime National Wildlife Refuge Complex and other marine resource trustees.

“The primary objective of the tests is to monitor seabird colonies along the coastline and offshore islands of Olympic Coast National Marine Sanctuary,” said Carol Bernthal, sanctuary superintendent. “We also plan to survey remote coastline and open waters for marine debris and other marine wildlife.”

The Puma is a 13-pound, battery-powered aircraft that can be hand-launched from any location on land or at sea from a boat and is controlled remotely. The aircraft can fly for up to two hours on a charge and cover a range of about 50 square miles.

If successful, unmanned aircraft technology could be used in marine protected areas worldwide.

Agencies throughout the state, including Grays Harbor, have submitted a proposal for a drone research and testing facility in Washington. The proposal provides a testing range over the Pacific Ocean near Grays Harbor for those developers needing “blue water” testing capability.

The final decisions for the flight center are scheduled to be made before December 31, 2013.

In the wake of the recent floods in Colorado, Falcon UAV has spent the last three days providing volunteer aerial services to the Boulder County Emergency Operations Center (EOC) and the Incident Management Team (IMT). On Thursday afternoon while all National Guard aircraft were grounded due to weather Falcon UAV was proud to have been the only aircraft that was able to take flight to support the flood efforts in Lyons.

Friday saw a reprieve in the weather and we are able to get a perfect flight off in the town of Longmont to capture aerial imagery for damage assesment at the intersection of the overflowing St Vrain river and equally inundated Left Hand Creek. In less than an hour the imagery was processed and provided to the Boulder EOC. Just as Falcon UAV was off to another damage assessment in Lyons, Colorado we were requested to standdown for National Guard helicopters now supporting evacuation efforts.

Enter FEMA…….

Early Saturday morning Falcon UAV was heading up to Lyons to complete a damage assessment mapping flight when we received a call from our Boulder EOC point of contact who notified us that FEMA had taken over operations and our request to fly drones was not only denied but more specifically we were told by FEMA that anyone flying drones would be arrested. Not being one to bow to federal bureaucrats we still went up to Lyons to do a site survey for how we can conduct a mission in the near future to provide an adequate damage assessment to this storm raveged community.

Where bridge to the south side of Lyons used to be

Road into Lyons, CO

While we were up there we noticed that Civil Air Patrol and private aircraft were authorized to fly over the small town tucked into the base of Rockies. Unfortunately due to the high terrain around Lyons and large turn radius of manned aircraft they were flying well out of a useful visual range and didn’t employ cameras or live video feed to support the recovery effort. Meanwhile we were grounded on the Lyons high school football field with two Falcons that could have mapped the entire town in less than 30 minutes with another few hours to process the data providing a near real time map of the entire town.

Falcon UAV would like to thank the Boulder County EOC and specifically Allen Bishop and Michael Chard (while they were running operations) for their common sense approach to drone operations, working to coordinate the airspace, as well as embracing this technology to help support the recovery effort. In contrast we are very disappointed in FEMAs response to actively prevent the use of UAVs and drone technology when these services were offered for free and at a time when manned helicopters could be used for more critical missions such as evacuations and high mountain search and rescues in inaccessible communities.

A drone the size of a small Cessna plane buzzing over the massive Rim fire has become a valuable tool as commanders use its real-time imagery to strategize their next move.

The remotely piloted plane began flying Wednesday morning after Incident Cmdr. Mike Wilkins requested the MQ-1 aircraft belonging to the California Air National Guard. It has since been giving fire commanders a bird’s-eye view of the 300-square-mile blaze in and around Yosemite National Park, which is now the sixth largest fire in state history.

Unmanned aircraft have been used sparingly on fires but are gaining value as a cheaper, more efficient tool for fire commanders to better understand how fires are behaving.

They are prized for their ability to beam real-time pictures directly to fire commanders, who can make tactical adjustments more quickly. The aircraft are equipped with infrared heat sensors and a swiveling camera operated remotely.

During a 20-hour mission Wednesday, the drone — taking off from the Victorville airport and operated from March Air Reserve Base in Riverside — alerted crews to a spot fire and provided a more comprehensive fire map.

Unlike manned planes and helicopters, drones are not grounded at night or unable to fly in high winds or smoke. They fly at about 18,000 feet and cost about $800 an hour to operate, Keegan said.

There are now 4,840 firefighters battling the Rim fire, which has been burning in the Stanislaus National Forest for nearly two weeks.

The blaze is 30% contained and has cost nearly $40 million to fight so far, officials said. The fire has burned about 301 square miles, an area bigger than Chicago or San Francisco, and destroyed at least 111 structures.

Fire crews in Yosemite were hoping to slow advancing flames by conducting large-scale backfire operations from Hetch Hetchy Reservoir south to Tioga Road.

The rate of spread of the massive fire has slowed in recent days and firefighters expect to have it fully contained by Sept. 10, officials said.